Benzo xanthene dyes

Whitaker JE, Haugland RP, Prendergast FG (1991) Spectral and photophysical studies of benzo[c]xanthenes dyes dual emission pH sensors. Anal Biochem 194 330-344... 

SNARF and SNAFL indicators are benzo[c]xanthene dyes that can be described as semi-naphthofluoresceins and semi-naphthorhodafluors, respectively, depending on whether the benzo[c]xanthene ring is substituted at the 10-position with oxygen or with nitrogen, respectively (Whitaker et al., 1991). These indicators, whose p K l values are in the physiological range, exhibit distinct emission bands for the pro-tonated and deprotonated forms so that emission ratio measurements are possible. In SNAFL, the acidic form is more fluorescent, whereas in SNARF, the basic form is more fluorescent. 

Whitaker J. E., Haugland R. P. and Prendergast F. G. (1991) Spectral and Photophysical Studies of Benzo[c]xanthene Dyes Dual Emission pH Sensors, Anal. Biochem. 194, 330—44. 

Brook, P. F. Lawry, J. Cooke, 1. D. Barratt, C. L. R. Measurement of intracellular pH in human spermatozoa hy flow cytometry with the benzo[c]xanthene dye SNAFL-1 A novel, single excitation, dual emission, molecular probe. Mol. Hum. Reprod. 1996, 2, 18-25. 

PO can be made degradable by means of additives. The types of additives include aromatic ketones (benzo-phenone and substituted benzophenones [47], qui-none), aromatic amines (trisphenylamine), polycyclic aromatic hydrocarbons (anthracene, certain dyes such as xanthene dyes), or transition metal organic compounds. The transition metal compounds of Fe, Co, Ni, Cr, Mn are widely used. Organo-soluble acetyl acetonates of many transition metals are photooxidants and transition metal carboxylates are also thermal pro-oxidants. Co acetylacetonate appears to be an effective catalyst for chemical degradation of PP in the marine environment. The preferred photoactivator system is ferric dibutyldithiocarbamate with a concentration range of 0.01. 1%. Scott has patented the use of organometallic compounds hke iron (ferric) dibutyldithiocarbamate or Ni-dibutyl-dithiocarbamate [48]. Cerium carboxylate [49] and carbon black are also used in such materials [50]. 

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